"Glass" Opens a New Window for
Seed Banks

When seeds freeze, their water and other cellular constituents have
properties similar to the silica-based glass used to make windows. Glasses make
seed cells very viscous, so molecules move slowly. The slower they move, the
slower their chemical reactions--and the slower a seed's aging rate.

Seeds stored at optimum conditions can last hundreds or thousands of years.
That reduces the need to regrow seedsthe most expensive part of
preserving germplasm.

The scientists' task is to determine how to keep stored seed alive and
capable of germinating and producing fruiting parts years later. They
continuously look for better ways to predict how seeds will respond to storage.
They turned to seed glasses after getting the idea from food technologists, who
use the glassy concept to study deterioration of frozen foods.

According to Christina
Walters at the Fort Collins lab, the glassy concept explains how frozen
seed cells respond to changing water contents and temperature. She has studied
glasses in dried and frozen seed of at least 30 plant species including bean,
pea, soybean and corn. She is looking for clues on the optimum combinations of
water content and temperature for storing seed.

For more details, see the September issue of Agricultural Research
magazine. The story about the seed glasses is also on the World Wide Web at: